Cissus quadrangularis mediated ecofriendly synthesis of copper oxide nanoparticles and its antifungal studies against Aspergillus niger, Aspergillus flavus

Aflatoxins in Peanut (Arachis hypogaea): Prevalence, Global Health Concern, and Management from an Innovative Nanotechnology Approach: A Mechanistic Repertoire and Future Direction

Arachis hypogaea is the most significant oilseed nutritious legume crop in agricultural trade across the world. It is recognized as a valued crop for its contributions to nourishing food, as a cooking oil, and for meeting the protein needs of people who are unable to afford animal protein. Currently, its production, marketability, and consumption are hindered because of Aspergillus species infection that consequently contaminates the kernels with aflatoxins. Regarding health concerns, humans and animals are affected by acute and chronic aflatoxin toxicity and millions of people are at high risk of chronic levels. Most methods used to store peanuts are traditional and serve effectively for short-term storage. Now the question for long-term storage has been raised, and this promptly finds potential approaches to the issue. It is imperative to reduce the aflatoxin levels in peanuts to a permissible level by introducing detoxifying innovations. Most of the detoxification reports mention physical, chemical, and biological techniques. However, many current approaches are impractical because of time consumption, loss of nutritional quality, or weak detoxifying efficiency. Therefore, it is crucial to investigate practical, economical, and green methods to control Aspergillus flavus that address current global food security problems. Herein, a green and economically revolutionary way is a nanotechnology that has demonstrated its potential to connect farmers to markets, elevate international marketability, improve human and animal health conditions, and enhance food quality and safety by the management of fungal diseases. Due to the antimicrobial potential of nanoparticles, they act as nanofungicides and have an incredible role in the control of aflatoxins. Nanoparticles have ultrasmall sizes and therefore penetrate the fungal body and invade the pathogen machinery, leading to fungal cell death by ROS production, mutation in DNA, disruption of organelles, and membrane leakage. This is the first mechanistic overview that unveils a comprehensive insight into aflatoxin contamination in peanuts, its prevalence, health effects, and management in addition to nanotechnological interventions that serve as a triple defense approach to detoxify aflatoxins. The optimum use of nanofungicides ensures food safety and the development of goals, especially "zero hunger".

Green and cost-effective biofabrication of copper oxide nanoparticles: Exploring antimicrobial and anticancer applications

Nanotechnology has made remarkable advancements in recent years, revolutionizing various scientific fields, industries, and research institutions through the utilization of metal and metal oxide nanoparticles. Among these nanoparticles, copper oxide nanoparticles (CuO NPs) have garnered significant attention due to their versatile properties and wide-range applications, particularly, as effective antimicrobial and anticancer agents. CuO NPs can be synthesized using different methods, including physical, chemical, and biological approaches. However, conventional chemical and physical approaches are expensive, resource-intensive, and involve the use of hazardous chemicals, which can pose risks to human health and the environment. In contrast, biological synthesis provides a sustainable and cost-effective alternative by eliminating chemical pollutants and allowing for the production of CuO NPs of tailored sizes and shapes. This comprehensive review focused on the green synthesis of CuO NPs using various biological resources, such as plants, microorganisms, and other biological derivatives. Current knowledge and recent trends in green synthesis methods for CuO NPs are discussed, with a specific emphasis on their biomedical applications, particularly in combating cancer and microbial infections. This review highlights the significant potential of CuO NPs in addressing these diseases. By capitalizing on the advantages of biological synthesis, such as environmental safety and the ability to customize nanoparticle characteristics, CuO NPs have emerged as promising therapeutic agents for a wide range of conditions. This review presents compelling findings, demonstrating the remarkable achievements of biologically synthesized CuO NPs as novel therapeutic agents. Their unique properties and mechanisms enable effective combating against cancer cells and various harmful microbial infections. CuO NPs exhibit potent anticancer activity through diverse mechanisms, including induction of apoptosis, inhibition of angiogenesis, and modulation of signaling pathways. Additionally, their antimicrobial activity manifests through various mechanisms, such as disrupting microbial membranes, generating reactive oxygen species, and interfering with microbial enzymes. This review offers valuable insights into the substantial potential of biologically synthesized CuO NPs as an innovative approach for future therapeutic interventions against cancer and microbial infections.

Fabrication of three-dimension hierarchical structure CuO nanoflowers and their antifungal mechanism against Bipolaris sorokiniana

Nanomaterials are widely investigated in sustainable agriculture owing to their unique physicochemical properties, especially Cu-based nanomaterial with eco-friendliness and essential for plant. However, the effect of CuO nanomaterial on Bipolaris sorokiniana (B. sorokiniana) is yet to be systematically understood. In this study, a three-dimension hierarchical structure CuO nanoflower (CuO NF) with ultrathin petals and excellent dispersibility in water was constructed and proved to have outstanding antifungal activity against B. sorokiniana with the inhibition rate of 86 % in mycelial growth, 74 % in mycelial dry weight and 75 % in conidial germination. Furthermore, the antifungal mechanism was assigned to the production of reactive oxygen species in intracellular caused by antioxidant mimicking activity of CuO NF to damage of cell membrane integrity and result cellular leakage. Additionally, the good control effect of CuO NF on wheat diseases caused by B. sorokiniana was demonstrated through pot experiment. This article firstly reveals the antifungal activity and mechanism of CuO NF on B. sorokiniana, and establishes the relationship between enzyme-like activity of CuO NF and its antifungal activity, which provides a promising application of Cu-based nanomaterial as nanofungicide in plant protection and a theoretical foundation for structure design of nanomaterials to improve their antifungal activities.

Study of synergistic effects induced by novel base composites on heavy metals removal and pathogen inactivation

The green-collar strategies for nanomaterial synthesis with novel structural competencies have received significant attention in nanotechnology owing to their potential benefits. The utilization of silica nanoparticles for wastewater treatment through heavy metal ions remediation is the focal point of the present study. With this intent, silica was extracted from bagasse ash by the sol-gel method and modified using chitosan. Chemical and physical characteristics of silica(S), silica/Chitosan (SCs), were reckoned through X-ray Powder Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscopy (SEM) and the efficiency of synthesized biomaterials for removing heavy metal ions. Cadmium and Lead from wastewater was evaluated by conducting closed batch experiments. Isotherm and kinetics models were applied to understand the adsorption mechanism. Results of heavy metal ions removal showed that the S possesses the highest removal efficiency of 88% for cadmium. Equilibrium was established within 56 min following a Langmuir isotherm model and pseudo-second-order reaction. The synthesized biomaterials were also tested against the fungal (Aspergillus Niger) and bacterial strains (Escherichia coli and Staphylococcus aureus) to determine their antimicrobial properties Maximum inhibition of 26 mm was shown by SCs for E.coli. Synthesized samples were not so effective for A.niger. The high adsorption potential of silica nanoparticles reveals their potential to treat wastewater containing inorganic pollutants like calcium and lead released from the sugar industry firsthand, thereby building a circular economy by controlling the pollution from source to sink. The synthesized silica nanoparticles and silica/chitosan biomaterials demonstrated high adsorption potential for heavy metal ions, making them promising candidates for integration into Algal Membrane Bioreactors to enhance wastewater treatment efficiency and remove toxic pollutants. Their multifunctional properties, including antimicrobial activity, also offer potential for improving microbial control within AMBRs, ensuring a more effective and sustainable wastewater treatment process.

Green synthesis of copper oxide nanoparticles from Murraya koenigii and its corrosion resistivity on Ti-6Al-4V dental alloy

The present work describes green-mediated copper oxide nanoparticles as a potential corrosion inhibitor for the dental alloy Ti-6Al-4V. The salt of copper was reduced to metal nanoparticles using Murraya koenigii leaves, which helps with the agglomeration and nanocluster formation through a reduction mechanism. The current synthesis is a single-step process and is cost-effective. The synthesized nanoparticle was characterized using UV, FTIR, XRD, Zeta potential and Particle size analyzer, SEM, and EDX. The particles were then electrodeposited on Ti-6Al-4V alloy, and the corrosion resistivity in the dental medium was analyzed using Electrochemical parameters such as Corrosion current, Corrosion potential, and anodic and cathodic intercepts through the Tafel and Nyquist plots. The synthesized nanoparticles showed characteristic absorbance at 359 nm. FTIR peaks confirm the phytochemical constituents present in the Murraya koenigii that accounts for the formation of nanoparticles. The XRD predicts the crystalline nature, which is further studied using SEM and EDX. The Zeta potential and Particle size analyzer confirms the negative-negative interactive nature of the synthesized CuO NPs. The NPs showed explicit corrosion inhibition properties with an overall inhibition efficiency of 58.15% and 25.6%, respectively. The study confirms the advantage of using Copper Oxide nanoparticles as a potential coating agent in dental implant alloys in increasing its corrosion efficiency.

Fabrication of chitosan nanocomposites loaded with biosynthetic metallic nanoparticles and their therapeutic investigation

The present research demonstrates the formation of zinc oxide nanoparticles facilitated by Cissus quadrangularis (CQ-ZnONPs) and subsequent synthesis of chitosan-conjugated nanocomposites (CQ-CS/ZnONCs) along with their biological assessment. The biosynthesized nanoparticles and nanocomposites were physicochemically characterized and therapeutically assessed for their antioxidant, antibacterial, and antidiabetic potential. The formation of CQ-ZnONPs and CQ-CS/ZnONCs was preliminarily validated by the change in color and subsequently by UV-visible spectroscopic analysis. The crystalline peaks associated with the CQ-ZnONPs in CQ-CS/ZnONCs were established by XRD analysis. Morphological evaluation of CQ-ZnONPs and CQ-CS/ZnONCs was carried out through FE-SEM and HRTEM studies. The particle size of the CQ-ZnONPs and CQ-CS/ZnONCs was 243.3 nm and 176.6 nm, with a PDI of 0.188 and 0.199, respectively. Nanoparticles and nanocomposites expressed Zeta potential of -15.7 mV and -16.2 mV, respectively. The CQ-ZnONPs and CQ-CS/ZnONCs showed good radical effectiveness with various in-vitro assays. The formulated nanoparticles and nanocomposites displayed significant antibacterial activity against the selected bacterial pathogens. CQ-CS/ZnONCs presented noteworthy α-amylase and α-glucosidase inhibitory effects compared to CQ-ZnONPs with IC50 of 73.66 ± 1.21 μg/mL and 87.59 ± 1.29 μg/mL, respectively. Moreover, the synthesized CQ-CS/ZnONCs demonstrated 98.92 ± 0.39% and 99.58 ± 0.16% wound contraction (at 7 and 14 mg, respectively), significantly (p < 0.05) higher than the standard and CQ-ZnONPs. Thus, the CQ-ZnONPs and CQ-CS/ZnONCs could effectively develop promising drug delivery systems to inhibit pathogens and chronic tissue repair.

Engineered Metal Oxide Nanoparticles as Fungicides for Plant Disease Control

Metal oxide nanoparticles are considered to be good alternatives as fungicides for plant disease control. To date, numerous metal oxide nanoparticles have been produced and evaluated as promising antifungal agents. Consequently, a detailed and critical review on the use of mono-, bi-, and tri-metal oxide nanoparticles for controlling phytopathogenic fungi is presented. Among the studied metal oxide nanoparticles, mono-metal oxide nanoparticles-particularly ZnO nanoparticles, followed by CuO nanoparticles -are the most investigated for controlling phytopathogenic fungi. Limited studies have investigated the use of bi- and tri-metal oxide nanoparticles for controlling phytopathogenic fungi. Therefore, more studies on these nanoparticles are required. Most of the evaluations have been carried out under in vitro conditions. Thus, it is necessary to develop more detailed studies under in vivo conditions. Interestingly, biological synthesis of nanoparticles has been established as a good alternative to produce metal oxide nanoparticles for controlling phytopathogenic fungi. Although there have been great advances in the use of metal oxide nanoparticles as novel antifungal agents for sustainable agriculture, there are still areas that require further improvement.

The Antimicrobial Applications of Nanoparticles in Veterinary Medicine: A Comprehensive Review

Nanoparticles (NPs) are nanoscaled particles sized from 1-100 nm, which can be composed of inorganic or organic compounds. NPs have distinctive morphology, size, structure, and surface features, which give them specific properties. These particular attributes make them interesting for biological and medical applications. Due to these characteristics, researchers are studying the possible aptness of numerous nanoparticles in veterinary medicine, such as the capacity to act as a drug delivery system. The use of these NPs as a possible bactericidal or bacteriostatic medication has been studied against different bacteria, especially multiresistant strains and the ones that cause mastitis disease. The antibiofilm property of these nanostructures has also already been proved. The antiviral activity has also been shown for some important viral animal diseases; the antifungal activity had been demonstrated against both pathogenic and mycotoxigenic species. Therefore, this review aimed to elucidate the main clinical and preventive veterinary applications of inorganic and organic nanoparticles.

Using inorganic nanoparticles to fight fungal infections in the antimicrobial resistant era

Fungal infections pose a serious threat to human health and livelihoods. The number and variety of clinically approved antifungal drugs is very limited, and the emergence and rapid spread of resistance to these drugs means the impact of fungal infections will increase in the future unless alternatives are found. Despite the significance and major challenges associated with fungal infections, this topic receives significantly less attention than bacterial infections. A major challenge in the development of fungi-specific drugs is that both fungi and mammalian cells are eukaryotic and have significant overlap in their cellular machinery. This lack of fungi-specific drug targets makes human cells vulnerable to toxic side effects from many antifungal agents. Furthermore, antifungal drug resistance necessitates higher doses of the drugs, leading to significant human toxicity. There is an urgent need for new antifungal agents, specifically those that can limit the emergence of new resistant species. Non-drug nanomaterials have primarily been explored as antibacterial agents in recent years; however, they are also a promising source of new antifungal candidates. Thus, this article reviews current research on the use of inorganic nanoparticles as antifungal agents. We also highlight challenges facing antifungal nanoparticles and discuss possible future research opportunities in this field. STATEMENT OF SIGNIFICANCE: Fungal infections pose a growing threat to human health and livelihood. The rapid spread of resistance to current antifungal drugs has led to an urgent need to develop alternative antifungals. Nanoparticles have many properties that could make them useful antimycotic agents. To the authors' knowledge, there is no published review so far that has comprehensively summarized the current development status of antifungal inorganic nanomaterials, so we decided to fill this gap. In this review, we discussed the state-of-the-art research on antifungal inorganic nanoparticles including metal, metal oxide, transition-metal dichalcogenides, and inorganic non-metallic particle systems. Future directions for the design of inorganic nanoparticles with higher antifungal efficacy and lower toxicity are described as a guide for further development in this important area.

Alpinia officinarum mediated copper oxide nanoparticles: synthesis and its antifungal activity against Colletotrichum gloeosporioides

Green synthesis offers an environmentally friendly and cost-effective alternative for the synthesis of copper oxide nanoparticles (CuO NPs). In this study, the synthesis of CuO NPs was optimized by using copper sulfate (CuSO₄) and the aqueous extract of Alpinia officinarum and its antifungal activity were investigated. The synthesized CuO NPs were characterized by UV-visible spectroscopy (UV-vis), X-ray diffraction (XRD), Fourier-transform infrared radiation spectroscopy (FT-IR), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), dynamic light scattering (DLS), and transmission electron microscopy (TEM). The results showed that the optimized conditions for the synthesis of CuO NPs were 1:2 ratio of extract and CuSO₄ solution, pH 7, and 30 °C. The characteristic UV-vis peak of A. officinarum synthesized CuO NPs was at 264 nm. The synthesized CuO NPs had high crystallinity and purity and were spherical in morphology with the mean size of 46.40 nm. The synthesized CuO NPs reduced the fungal growth of Colletotrichum gloeosporioides in a dose-dependent manner. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of the CuO NPs were 125 μg·mL^-1 and 500 μg·mL^-1, respectively. The antifungal activity of CuO NPs may be attributed to its ability to deform the structure of fungal hyphae, induce excessive reactive oxygen species accumulation and lipid peroxidation in fungi, disrupt the mycelium cell membrane, and result cellular leakage.

Green synthesis of nanoparticles using botanicals and their application in management of fungal phytopathogens: a review

Green synthesis of nanoparticles is an emerging aspect in plant disease management that blends nanotechnology and plant-derived ingredients to produce a biocontrol formulation. Different physical and chemical processes employed in the synthesis of nanoparticles are polluting, expensive, and also release hazardous by- products. The range of secondary metabolites present in plants makes them efficient reducing and stabilizing agent during the synthesis process. These metabolites serve a vital role in plant defense against the invasion of phytopathogens including fungi, bacteria, viruses, insect pests, etc. The plant metabolites, such as sugars, terpenoids, polyphenols, alkaloids, phenolic acids, and proteins, have been shown to be crucial in the reduction of metal ions into nanoparticles. In green synthesis of nanoparticles, the plant extracts are used as potential reducing and capping. This also restricts the formation of clusters or aggregates and improves the colloidal stability. The nanoparticles exhibit excellent antimycotic against a variety of phytopathogens and are very efficient in managing plant diseases. The aim of this review is to highlight plants, phytochemicals exhibiting antifungal properties, green synthesis of nanoparticles using plant material and their antimycotic activity.

New frontiers of invasive plants for biosynthesis of nanoparticles towards biomedical applications: A review

Above 1000 invasive species have been growing and developing ubiquitously on Earth. With extremely vigorous adaptability, strong reproduction, and spreading powers, invasive species have posed an alarming threat to indigenous plants, water quality, soil, as well as biodiversity. It was estimated that an economic loss of billions of dollars or equivalent to 1 % of gross domestic product as a consequence of lost crops, control efforts, and damage costs caused by invasive plants in the United States. While eradicating invasive plants from the ecosystems is practically infeasible, taking advantage of invasive plants as a sustainable, locally available, and zero-cost source to provide valuable phytochemicals for bionanoparticles fabrication is worth considering. Here, we review the harms, benefits, and role of invasive species as important botanical sources to extract natural compounds such as piceatannol, resveratrol, and quadrangularin-A, flavonoids, and triterpenoids, which are linked tightly to the formation and application of bionanoparticles. As expected, the invasive plant-mediated bionanoparticles have exhibited outstanding antibacterial, antifungal, anticancer, and antioxidant activities. The mechanism of biomedical activities of the invasive plant-mediated bionanoparticles was insightfully addressed and discussed. We also expect that this review not only contributes to efforts to combat invasive plant species but also opens new frontiers of bionanoparticles in the biomedical applications, therapeutic treatment, and smart agriculture.

Synthesis, biomedical applications, and toxicity of CuO nanoparticles

Versatile nature of copper oxide nanoparticles (CuO NPs) has made them an imperative nanomaterial being employed in nanomedicine. Various physical, chemical, and biological methodologies are in use for the preparation of CuO NPs. The physicochemical and biological properties of CuO NPs are primarily affected by their method of fabrication; therefore, selectivity of a synthetic technique is immensely important that makes these NPs appropriate for a specific biomedical application. The deliberate use of CuO NPs in biomedicine questions their biocompatible nature. For this reason, the present review has been designed to focus on the approaches employed for the synthesis of CuO NPs; their biomedical applications highlighting antimicrobial, anticancer, and antioxidant studies; and most importantly, the in vitro and in vivo toxicity associated with these NPs. This comprehensive overview of CuO NPs is unique and novel as it emphasizes on biomedical applications of CuO NPs along with its toxicological assessments which would be useful in providing core knowledge to researchers working in these domains for planning and conducting futuristic studies. KEY POINTS: • The recent methods for fabrication of CuO nanoparticles have been discussed with emphasis on green synthesis methods for different biomedical approaches. • Antibacterial, antioxidant, anticancer, antiparasitic, antidiabetic, and antiviral properties of CuO nanoparticles have been explained. • In vitro and in vivo toxicological studies of CuO nanoparticles exploited along with their respective mechanisms.

Novel Copper Oxide Bio-Nanocrystals to Target Outer Membrane Lectin of Vancomycin-Resistant Enterococcus faecium (VREfm): In Silico, Bioavailability, Antimicrobial, and Anticancer Potential

In present study, we used Olea europaea leaf extract to biosynthesize in situ Copper Oxide nanocrystals (CuO @OVLe NCs) with powerful antibacterial and anti-cancer capabilities. Physio-chemical analyses, such as UV/Vis, FTIR, XRD, EDX, SEM, and TEM, were applied to characterize CuO @OVLe NCs. The UV/Vis spectrum demonstrated a strong peak at 345 nm. Furthermore, FTIR, XRD, and EDX validated the coating operation's contact with colloidal CuO @OVLe NCs. According to TEM and SEM analyses, CuO @OVLe NCs exhibited a spherical shape and uniform distribution of size with aggregation, for an average size of ~75 nm. The nanoparticles demonstrated a considerable antibacterial effect against E. faecium bacterial growth, as well as an increased inhibition rate in a dose-dependent manner on the MCF-7, PC3, and HpeG2 cancer cell lines and a decreased inhibition rate on WRL-68. Molecular docking and MD simulation were used to demonstrate the high binding affinity of a ligand (Oleuropein) toward the lectin receptor complex of the outer membrane to vancomycin-resistant E. faecium (VREfm) via amino acids (Leu 195, Thr 288, His 165, and Ser 196). Hence, our results expand the accessibility of OVLe's bioactive components as a promising natural source for the manufacture of physiologically active components and the creation of green biosynthesis of metal nanocrystals.

Antifungal Effect of Nanoparticles against COVID-19 Linked Black Fungus: A Perspective on Biomedical Applications

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly transmissible and pathogenic coronavirus that has caused a 'coronavirus disease 2019' (COVID-19) pandemic in multiple waves, which threatens human health and public safety. During this pandemic, some patients with COVID-19 acquired secondary infections, such as mucormycosis, also known as black fungus disease. Mucormycosis is a serious, acute, and deadly fungal infection caused by Mucorales-related fungal species, and it spreads rapidly. Hence, prompt diagnosis and treatment are necessary to avoid high mortality and morbidity rates. Major risk factors for this disease include uncontrolled diabetes mellitus and immunosuppression that can also facilitate increases in mucormycosis infections. The extensive use of steroids to prevent the worsening of COVID-19 can lead to black fungus infection. Generally, antifungal agents dedicated to medical applications must be biocompatible, non-toxic, easily soluble, efficient, and hypoallergenic. They should also provide long-term protection against fungal growth. COVID-19-related black fungus infection causes a severe increase in fatalities. Therefore, there is a strong need for the development of novel and efficient antimicrobial agents. Recently, nanoparticle-containing products available in the market have been used as antimicrobial agents to prevent bacterial growth, but little is known about their efficacy with respect to preventing fungal growth, especially black fungus. The present review focuses on the effect of various types of metal nanoparticles, specifically those containing silver, zinc oxide, gold, copper, titanium, magnetic, iron, and carbon, on the growth of various types of fungi. We particularly focused on how these nanoparticles can impact the growth of black fungus. We also discussed black fungus co-infection in the context of the global COVID-19 outbreak, and management and guidelines to help control COVID-19-associated black fungus infection. Finally, this review aimed to elucidate the relationship between COVID-19 and mucormycosis.

Biosynthesis and biophysical elucidation of CuO nanoparticle from Nyctanthes arbor-tristis Linn Leaf

Copper oxide nanoparticles (CuO NPs) synthesis using an environmentally benign approach, as well as their antibacterial properties. Copper sulphate pentahydrate (CuSO₄.5H₂O) of different concentrations (2 mM, 5 mM and 10 mM) and aqueous Nyctanthes arbor-tristis leaf extract were used to make the CuO NPs. The synthesised CuO NPs are characterised by UV-vis spectroscopy, X-ray diffractometer (XRD), Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). UV-vis spectroscopy confirmed the presence of CuO NPs. The functional groups of the active components were identified using the FTIR spectra of the control (leaf extract) and CuO NPs. SEM pictures revealed that the particles were rectangular, truncated triangle and spherical in shape, with sizes ranging between 4.9 nm, 18.4 nm and 23.8 nm determined using X-ray diffraction. The antibacterial activity of the produced CuO NPs was further evaluated using the well diffusion method. By observing inhibition zones around each well, the nanoparticles were revealed to have broad antibacterial action against human pathogenic bacterial strains Escherichia coli and Staphylococcus aureus withs the 7 ± 0.70-mm and 7 ± 0.21-mm inhibitory zone size respectively followed by 08 μg/mL and 2.5 μg/mL MIC respectively. Thus, these outputs concluded that the CuO NPs exhibited miraculous effect and it might be boon towards nanomedical science, pharmaceuticals and health industries. KEY POINTS: • Biosynthesis of CuO nanoparticle • Multifaceted utilization • Broad spectrum antimicrobial activity.

Enhanced photocatalytic activity of novel Canthium coromandelicum leaves based copper oxide nanoparticles for the degradation of textile dyes

The present study focused to synthesize the copper oxide nanoparticles (CuONPs) using novel Canthium coromandelicum leaves in a cost-effective, easy, and sustainable approach. The obtained Canthium coromandelicum-copper oxide nanoparticles (CC-CuONPs) were characterized using UV-Visible spectroscopy, FT-IR analysis, FESEM, HR-TEM imaging, and XRD study. The XRD pattern verified the development of crystalline CC-CuONPs with an average size of 33 nm. The biosynthesized CC-CuONPs were roughly spherical, according to HR-TEM and FESEM analyses. FT-IR research verified the existence of functional groups involved in CC-CuONPs production. Cu and O₂ have high-energy signals of 78.32% and 12.78%, respectively, according to data from EDX. The photocatalytic evaluation showed that synthesized CC-CuONPs have the efficiency of degrading methylene blue (MB) and methyl orange (MO) by 91.32%, 89.35% respectively. The findings showed that biosynthesized CC-CuONPs might effectively remove contaminants in an environmentally acceptable manner.

Biosynthesized δ-Bi2O3 Nanoparticles from Crinum viviparum Flower Extract for Photocatalytic Dye Degradation and Molecular Docking

Bioinspired delta-bismuth oxide nanoparticles (δ-Bi₂O₃ NPs) have been synthesized using a greener reducing agent and surfactant via co-precipitation method. The originality of this work is the use of Crinum viviparum flower extract for the first time for the fabrication of NPs, which were further calcined at 800 °C to obtain δ-Bi₂O₃ NPs. Physicochemical studies such as FTIR spectroscopy and XPS confirmed the formation of Bi₂O₃ NPs, whereas XRD and Raman verified the formation of the cubic delta (δ) phase of Bi₂O₃ NPs. However, HRTEM revealed the spherical shape with diameter 10-20 nm, while BET studies expose mesoporous nature with a surface area of 71 m²/gm. The band gap for δ-Bi₂O₃ NPs was estimated to be 3.45 eV, which ensured δ-Bi₂O₃ to be a promising photocatalyst under visible-light irradiation. Therefore, based on the results of physicochemical studies, the bioinspired δ-Bi₂O₃ NPs were explored as active photocatalysts for the degradation of toxic dyes, viz., Thymol blue (TB) and Congo red (CR) under visible-light irradiation. The study showed 98.26% degradation of TB in 40 min and 69.67% degradation of CR in 80 min by δ-Bi₂O₃ NPs. The photogenerated holes and electrons were found responsible for this enhancement. Furthermore, molecular docking investigations were also performed for δ-Bi₂O₃ NPs to understand its biological function as New Delhi metallo-β-lactamase 1 (NDM-1) [PDB ID 5XP9] enzyme inhibitor, and studies revealed good interaction with various amino acid residues and found good hydrogen bonding with a fine pose energy of -3.851 kcal/mole.

New frontiers in the plant extract mediated biosynthesis of copper oxide (CuO) nanoparticles and their potential applications: A review

Copper oxide nanoparticles (CuO NPs) are one of the most widely used nanomaterials nowadays. CuO NPs have numerous applications in biological processes, medicine, energy devices, environmental remediation, and industrial fields from nanotechnology. With the increasing concern about the energy crisis and the challenges of chemical and physical approaches for preparing metal NPs, attempts to develop modern alternative chemistry have gotten much attention. Biological approaches that do not produce toxic waste and therefore do not require purification processes have been the subject of numerous studies. Plants may be extremely useful in the study of biogenic metal NP synthesis. This review aims to shed more light on the interactions between plant extracts and CuO NP synthesis. The use of living plants for CuO NPs biosynthesis is a cost-effective and environmentally friendly process. To date, the findings have revealed many aspects of plant physiology and their relationships to the synthesis of NPs. The current state of the art and potential challenges in the green synthesis of CuO NPs are described in this paper. This study found a recent increase in the green synthesis of CuO NPs using various plant extracts. As a result, a thorough explanation of green synthesis and stabilizing agents for CuO NPs made from these green sources is given. Additionally, the multifunctional applications of CuO NPs synthesized with various plant extracts in environmental remediation, sensing, catalytic reduction, photocatalysis, diverse biological activities, energy storage, and several organic transformations such as reduction, coupling, and multicomponent reactions were carefully reviewed. We expect that this review could serve as a useful guide for readers with a general interest in the plant extract mediated biosynthesis of CuO NPs and their potential applications.

Inhibiting the PI3K/AKT/mTOR signalling pathway with copper oxide nanoparticles from Houttuynia cordata plant: attenuating the proliferation of cervical cancer cells

Cervical cancer is the most important female genital cancer that develops from the cervix, a lower part of uterus. Houttuynia cordata is ubiquitously present in Asian countries, and traditionally prescribed to treat infections and oedema. Our study emphasizes on biological synthesis route for developing copper nanocomplex using Houttuynia cordata (Hc-CuONPs) plant extract. The UV-visible spectroscopy study of Hc-CuONPs revealed the maximum peak at 350 nm, which proved the formation of Hc-CuONPs and FT-IR absorption peaks revealed the existence of different functional groups. The results of high-resolution TEM and X-ray diffraction studies revealed that the Hc-CuONPs have face centred cubic structure along with 40-45 nm in size. The temperature conditions of the synthesized Hc-CuONPs were spherical and circular morphologies. Furthermore, the Hc-CuONPs (IC50=5 µg/ml) exhibited toxicity on cervical cancer cells (HeLa). The intracellular reactive oxygen species (ROS) level in the control and Hc-CuONPs-treated HeLa cells was monitored by DCFH-DA staining and the apoptotic cell death was detected by using the dual (AO/EtBr) staining, propidium iodide and DAPI staining assays. Our results from the fluorescent staining analysis evidenced that the Hc-CuONPs have inhibited the cell proliferation and promoted the apoptotic cell death in HeLa cells. The Hc-CuONPs promoted the apoptosis by targeting the PI3K/Akt signalling pathways in HeLa cells. Our results explored that the Hc-CuONPs are effective against in vitro HeLa cancer cells.

Microbial cell factories a new dimension in bio-nanotechnology: exploring the robustness of nature

Bio-based nanotechnology has its existence in biological dimensions e.g. microbial cell factories (bacteria, fungi. algae, yeast, cyanobacteria) plants, and biopolymers. They provide multipurpose biological platforms to supply well-designed materials for diverse nano-biotechnological applications. The "green or bio-based synthesis of nanoparticles (NPs)" has witnessed a research outburst in the past decade. The bio-based synthesis of NPs using microbial cell factories is a benign process and requires mild conditions for the synthesis with end products being less/non-toxic. As a result, its application has extended in multitudinous industries including environment, cosmetics, and pharmaceutical. Thus, the present review summarizes all the significant aspects of nanotechnology and the reason to switch towards the bio-based synthesis of NPs using microbial cell factories. It consists of a detailed description of the bio-based methods employed for the synthesis and classification of NPs. Also, a comprehensive study on the application of bio-based NPs in the various industrial and biotechnological domains has been discussed. The limitation and its solution would help identify the applicability of NPs to "identified and unidentified" sectors.

Toxicity of Nanoparticles in Biomedical Application: Nanotoxicology

Nanoparticles are of great importance in development and research because of their application in industries and biomedicine. The development of nanoparticles requires proper knowledge of their fabrication, interaction, release, distribution, target, compatibility, and functions. This review presents a comprehensive update on nanoparticles' toxic effects, the factors underlying their toxicity, and the mechanisms by which toxicity is induced. Recent studies have found that nanoparticles may cause serious health effects when exposed to the body through ingestion, inhalation, and skin contact without caution. The extent to which toxicity is induced depends on some properties, including the nature and size of the nanoparticle, the surface area, shape, aspect ratio, surface coating, crystallinity, dissolution, and agglomeration. In all, the general mechanisms by which it causes toxicity lie on its capability to initiate the formation of reactive species, cytotoxicity, genotoxicity, and neurotoxicity, among others.

Synthesis of TiO2 nanoparticles by chemical and green synthesis methods and their multifaceted properties

In this present work, Titanium dioxide nanoparticles (TiO2 NPs) successfully synthesized using the chemical as well as the green synthesis routine. The ethanol provoked the chemical reduction of ions. In the green synthesis, jasmine flower extract was used as a reducing and stabilizing agent because it contains alkaloids, coumarins, flavonoids. The Rutile phase of TiO2 NPs with an average crystalline size of 31–42 nm was revealed from the XRD pattern. From the UV–Visible spectroscopy, the optically active region of TiO2 NPs at 385 nm represents the visible region spectrum. The Ti–O–Ti and Ti–O vibration bond formation confirms the formation of TiO2 NPs. The SEM image of TiO2 NPs reveals that the spherical shaped NPs with randomly arranged manner. The obtained results have revealed that the property of TiO2 nanoparticles was similar in both processes. The Photodegradation of methylene blue dye was investigated and resulted in the maximum degradation efficiency of 92% is achieved at 120 min of irradiation. The Photodegradation study shows the biosynthesized TiO2 NPs exhibits a higher degradation efficiency compared to chemically synthesized TiO2 NPs. The antibacterial activity of prepared TiO2 NP’s was studied using grams-positive and gram-negative strains. The biological activities of green synthesized TiO2 NPs are enhanced compared to the chemically synthesized TiO2 NPs. Hence the degradation efficiency and zone inhibition layer indicate that the prepared TiO2 NPs are the potential candidate for environmental and biomedical applications.

Graphic abstract

Antibacterial Cotton Fabric Functionalized with Copper Oxide Nanoparticles

Textiles functionalized with cupric oxide (CuO) nanoparticles have become a promising option to prevent the spread of diseases due to their antimicrobial properties, which strongly depend on the structure and morphology of the nanoparticles and the method used for the functionalization process. This article presents a review of work focused on textiles functionalized with CuO nanoparticles, which were classified into two groups, namely, in situ and ex situ. Moreover, the analyzed bacterial strains, the resistance of the antimicrobial properties of textiles to washing processes, and their cytotoxicity were identified. Finally, the possible antimicrobial mechanisms that could develop in Gram-positive and Gram-negative bacteria were described.

Copper-Chitosan Nanocomposite Hydrogels Against Aflatoxigenic Aspergillus flavus from Dairy Cattle Feed

The integration of copper nanoparticles as antifungal agents in polymeric matrices to produce copper polymer nanocomposites has shown excellent results in preventing the growth of a wide variety of toxigenic fungi. Copper-chitosan nanocomposite-based chitosan hydrogels (Cu-Chit/NCs hydrogel) were prepared using a metal vapor synthesis (MVS) and the resulting samples were described by transmission electron microscopy (TEM), X-ray fluorescence analysis (XRF), and small-angle X-ray scattering (SAXS). Aflatoxin-producing medium and VICAM aflatoxins tests were applied to evaluate their ability to produce aflatoxins through various strains of Aspergillus flavus associated with peanut meal and cotton seeds. Aflatoxin production capacity in four fungal media outlets revealed that 13 tested isolates were capable of producing both aflatoxin B1 and B2. Only 2 A. flavus isolates (Af11 and Af 20) fluoresced under UV light in the A. flavus and parasiticus Agar (AFPA) medium. PCR was completed using two specific primers targeting aflP and aflA genes involved in the synthetic track of aflatoxin. Nevertheless, the existence of aflP and aflA genes indicated some correlation with the development of aflatoxin. A unique DNA fragment of the expected 236 bp and 412 bp bands for aflP and aflA genes in A. flavus isolates, although non-PCR fragments have been observed in many other Aspergillus species. This study shows the antifungal activity of Cu-Chit/NCs hydrogels against aflatoxigenic strains of A. flavus. Our results reveal that the antifungal activity of nanocomposites in vitro can be effective depending on the type of fungal strain and nanocomposite concentration. SDS-PAGE and native proteins explain the apparent response of cellular proteins in the presence of Cu-Chit/NCs hydrogels. A. flavus treated with a high concentration of Cu-Chit/NCs hydrogels that can decrease or produce certain types of proteins. Cu-Chit/NCs hydrogel decreases the effect of G6DP isozyme while not affecting the activity of peroxidase isozymes in tested isolates. Additionally, microscopic measurements of scanning electron microscopy (SEM) showed damage to the fungal cell membranes. Cu-Chit/NCS hydrogel is an innovative nano-biopesticide produced by MVS is employed in food and feed to induce plant defense against toxigenic fungi.

Green synthesis of copper oxide nanoparticles for biomedical application and environmental remediation

Recent development in nanoscience and nanotechnology has contributed to the wide applications of metal and metal oxides nanoparticles in several field of sciences, research institutes and industries. Among all metal oxides, copper oxide nanoparticles (CuONPs) has gained more attention due to its distinctive properties and applications. The high cost of reagents, equipment and environmental hazards associated with the physical and chemical methods of synthesizing CuONPs has been a major setback. In order to puffer solution to the aforementioned challenges by reducing environmental pollution and production of cheaper nanoparticles with good properties and efficiency, this review focus on collection of comprehensive information from recent developments in the synthesis, characterization and applications from previous scientific findings on biological method of synthesizing CuONPs due to the acclaimed advantages of been cheap, environmentally friendly, convenient and possibility of been scale up in into large scale production reported by numerous researchers. Our finding also support the synthesis of CuONPs from plant sources due to relative abundance of plants for the production of reducing and stabilizing agents required for CuONPs synthesis, potential efficiency of plant biomolecules in enhancing the toxicity effect of CuONPs against microbes, prevention of environmental pollution due of nontoxic chemicals and degradation effectiveness of CuONPs synthesized from plant sources. Furthermore, this study provide useful information on the rapid synthesis of CuONPs with desired properties from plant extracts.

Biosynthesis of Flower-Shaped CuO Nanostructures and Their Photocatalytic and Antibacterial Activities

Copper oxide nanoflowers (CuO-NFs) have been synthesized through a novel green route using Tulsi leaves-extracted eugenol (4-allyl-2-methoxyphenol) as reducing agent. Characterizations results reveal the growth of crystalline single-phase CuO-NFs with monoclinic structure. The prepared CuO-NFs can effectively degrade methylene blue with 90% efficiency. They also show strong barrier against E. coli (27 ± 2 mm) at the concentration of 100 µg mL-1, while at the concentration of 25 µg mL-1 weak barrier has been found against all examined bacterial organisms. The results provide important evidence that CuO-NFs have sustainable performance in methylene blue degradation as well as bacterial organisms.

Engineered nanomaterials inhibit Podosphaera pannosa infection on rose leaves by regulating phytohormones

In the present study, we investigated the antifungal effects of engineered nanomaterials (ENMs) against Podosphaera pannosa (P. pannosa), a fungal pathogen that causes powdery mildew on plants in the rose family. Four commercial ENMs, including multi-wall carbon nanotubes (MWCNTs), reduced graphene oxide (rGO), copper oxide (CuO) nanoparticles (NPs) and titanium dioxide (TiO₂) NPs, were used to prepare 50 or 200 mg/L NP suspensions in deionized water. Rose leaves in water-agar plates were sprayed by different ENM suspensions mixed with P. pannosa conidia. After a 19-day standard infection test, the growth of P. pannosa on rose leaves was evaluated. All four ENMs inhibited infection by P. pannosa at the concentration 200 mg/L, whereas only CuO NPs decreased fungal growth at 50 mg/L. The phytohormone content of the leaves was measured across all treatments to investigate potential ENMs antifungal mechanisms. The results suggest that ENMs increased plant resistance to fungal infection by altering the content of endogenous hormones, particularly zeatin riboside (ZR). Our study demonstrates that ENMs exhibited distinctly antifungal effects against P. pannosa on roses, and could be utilized as a novel plant protection strategy after a comprehensive assessment of potential environmental risk.

Phytosynthesis of nearly monodisperse CuO nanospheres using Phyllanthus reticulatus/Conyza bonariensis and its antioxidant/antibacterial assays

In the present article we have developed an eco-friendly, phytosynthetic, cost-effective and straightforward method for the synthesis of nearly monodisperse CuO nanospheres (NSP) using leaf extracts of medicinal plants Phyllanthus reticulatus (PR) and Conyza bonariensis (CB) as novel green reducing agents. Copper nitrate (Cu (NO₃)₂) was used as a precursor. The stoichiometric ratio of both leaf extracts (PR/CB) and Cu(NO₃)₂ was standardized for the synthesis of NSP. During formation of CuO NSP, a color of solution gradually changed from light greenish-blue to black with a number of intermediate stages and it correlated to the reduction reaction catalyzed by phytochemicals. As-synthesized materials were characterized in detail at the structural, electronic level and morphological authentication by XRD, FT-IR, EDS, UV-DRS, Raman, XPS, SEM, TEM, BET and AFM. SEM studies of phytosynthesized materials revealed nearly monodisperse nanospheres, while TEM rendered average particles size 4-14 nm. Also, AFM profiles suggested a homogenized nature of the nanospheres. Then, the antioxidant property was obtained by α, α-diphenyl-β-picrylhydrazyl (DPPH). Ethanolic, methanolic extracts were used for the antioxidant activity, while ascorbic acid was used as a standard medium. Each plant extract exhibited noteworthy antioxidant activity. Moreover, the antibacterial activity of CuO NSP (PR/CB) was tested against human pathogenic bacteria viz. gram-positive Staphylococcus aureus, Klebsiella pneumoniae, and gram-negative Escherichia coli. Result rendered effective antibacterial activity against Escherichia coli.

Green synthesis of metal oxide nanostructures using naturally occurring compounds for energy, environmental, and bio-related applications

This review summarizes the synthesis and functional applications of metal oxide nanostructures synthesized using plant-derived phytochemicals for energy, environmental, and biomedical applications.

Nanoparticles as a Solution for Eliminating the Risk of Mycotoxins

Mycotoxins are toxic secondary metabolites produced by certain filamentous fungi. The occurrence of mycotoxins in food and feed causes negative health impacts on both humans and animals. Clay binders, yeast cell walls, or antioxidant additives are the most widely used products for mycotoxin elimination to reduce their impact. Although conventional methods are constantly improving, current research trends are looking for innovative solutions. Nanotechnology approaches seem to be a promising, effective, and low-cost way to minimize the health effects of mycotoxins. This review aims to shed light on the critical knowledge gap in mycotoxin elimination by nanotechnology. There are three main strategies: mold inhibition, mycotoxin adsorption, and reducing the toxic effect via nanoparticles. One of the most promising methods is the use of carbon-based nanomaterials. Graphene has been shown to have a huge surface and high binding capacity for mycotoxins. Attention has also been drawn to polymeric nanoparticles; they could substitute adsorbents or enclose any substance, which would improve the health status of the organism. In light of these findings, this review gives new insights into possible future research that might overcome challenges associated with nanotechnology utilization for mycotoxin elimination from agricultural products.

CuO and CeO2 Nanostructures Green Synthesized Using Olive Leaf Extract Inhibits the Growth of Highly Virulent Multidrug Resistant Bacteria

One of the major challenges of nano-biotechnology is to engineer potent antimicrobial nanostructures (NS) with high biocompatibility. Keeping this in view, we have performed aqueous olive leaf extract mediated one pot facile synthesis of CuO-NS and CeO2-NS. Prepared NS were homogenous, less than 26 nm in size, and small crystallite units as revealed by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses. Fourier transform infrared spectroscopy (FTIR) of CuO-NS and CeO2-NS showed typical Cu-O prints around 592-660 cm-1 and Ce-O bond vibrations at 453 cm-1. The successful capping of CuO-NS and CeO2-NS by compounds present in the plant extract was further validated by high performance liquid chromatography (HPLC) and thermal gravimetric analysis (TGA). Active phyto-chemicals from the leaf extract simultaneously acted as strong reducing as well as capping agent in the NS synthesis. NS engineered in the present study showed antibacterial potential at extremely low concentration against highly virulent multidrug-resistant (MDR) gram-negative strains (Escherichia coli, Enterobacter cloacae, Acinetobacter baumannii and Pseudomonas aeruginosa), alarmed by World Health Organization (WHO). Furthermore, CuO-NS and CeO2-NS did not show any cytotoxicity on HEK-293 cell lines and Brine shrimp larvae indicating that the NS green synthesized in the present study are biocompatible.

Secondary Metabolites in the Green Synthesis of Metallic Nanoparticles

The ability of organisms and organic compounds to reduce metal ions and stabilize them into nanoparticles (NPs) forms the basis of green synthesis. To date, synthesis of NPs from various metal ions using a diverse array of plant extracts has been reported. However, a clear understanding of the mechanism of green synthesis of NPs is lacking. Although most studies have neglected to analyze the green-synthesized NPs (GNPs) for the presence of compounds derived from the extract, several studies have demonstrated the conjugation of sugars, secondary metabolites, and proteins in these biogenic NPs. Despite several reports on the bioactivities (antimicrobial, antioxidant, cytotoxic, catalytic, etc.) of GNPs, only a handful of studies have compared these activities with their chemically synthesized counterparts. These comparisons have demonstrated that GNPs possess better bioactivities than NPs synthesized by other methods, which might be attributed to the presence of plant-derived compounds in these NPs. The ability of NPs to bind with organic compounds to form a stable complex has huge potential in the harvesting of precious molecules and for drug discovery, if harnessed meticulously. A thorough understanding of the mechanisms of green synthesis and high-throughput screening of stabilizing/capping agents on the physico-chemical properties of GNPs is warranted to realize the full potential of green nanotechnology.